Methods for fabricating three dimensional anisotropic thin films and products produced thereby

ABSTRACT

A three dimensional structure comprising at least two materials capable of being deposited by vapor deposition. The structure is fabricated by the controlled vapor deposition of the materials onto a substrate.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/907,117, filed on Jul. 17, 2001, which claimsthe benefit of U.S. Provisional Application No. 60/232,950 filed Sep.15, 2000. These earlier applications are incorporated herein by way ofreference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to deposition methods such as chemicalvapor and physical vapor depositions for the production ofnanostructured thin films, and in particular to the production ofthree-dimensional anisotropic thin films.

[0003] Chemical vapor deposition (CVD) and physical vapor deposition(PVD) techniques are today routine technologies for the deposition ofthin single and multi-layer films. These thin films are commonly usedfor optical, electrical, ornamental, wear resistant, and decorativeapplications. The films allow very small amounts of material to bedeposited onto a substrate. These films allow not only a minimum ofotherwise expensive materials to be used, but also enableminiaturization, enhancement of optical properties, precise electricalperformance, user defined structures/morphology, and a profusion ofsurface specific compositions and surface treatments. However, whenthese conventional deposition techniques are used to deposit multiplecomponents into a single film, the resulting film usually exhibits thelesser properties of the two components. For example, multi-layerstructures which include one hard layer such as TiN (titanium nitride),and one soft layer such as gold (Au), do not exhibit the strength ofTiN. Rather they are limited by the mechanical adhesive strength of thegold layer. At the same time the desired optical or electricalproperties of gold are diminished due to the TiN phase. It is primarilyto these difficulties in thin film fabrication methods that the presentinvention is directed. Other novel structures made possible by themethod of the invention, including unique single component anisotropicthin films and post method deposited component films, will be furtherdescribed below.

[0004] It is therefore a primary object of the present invention toprovide a method for fabricating three dimensional, anisotropicnanostructured thin films.

[0005] A further object of the invention is to provide a method forfabricating nanostructured wear resistant thin film coatings withanisotropic properties.

[0006] An additional object of the invention is to provide a method forfabricating sculptured nanostructures.

[0007] Still another object of the invention is to provide a method forfabricating gold nanotructured thin film coatings with anisotropicelectrical conductivity properties.

[0008] Yet another object of the invention is to provide a method forfabricating nanostructured composite conductive films.

SUMMARY OF THE INVENTION

[0009] These and other objects are obtained with the present inventionof a method for fabricating three-dimensional anisotropic thin films.

[0010] The term “Nanostructure” as used herein refers to structures withdimensions in a range between 1 to less than 100 nanometers (nm), aspresently defined in the industry, and only defining the thickness rangeof the anisotropic lattice depositions produced by the method of theinvention without restricting the ability for additional stratificationor film growth.

[0011] Thin films of this type are commonly deposited onto a substrate,either in single or multiple layers, by means of chemical vapordeposition and physical vapor deposition techniques. A typical physicalvapor deposition involves placing an object to be coated or upon which afilm is to be deposited (substrate) within a vacuum chamber which alsocontains one or more target materials. A vacuum pump then produces avacuum within the chamber. A small quantity of a gas, as, for example,argon, is admitted to the chamber. A power source such as a DCmagnetron, or an RF diode power source, or an RF magnetron is thenturned on, which causes the Ar (argon) to ionize and ion bombard thetarget material, which causes sputtering of the target material withsubsequent sputtering deposition of the target material onto thesubstrate. The described method is also applicable to reactivedepositions. These PVD techniques have found wide applications in microelectronics, decorative coatings, machine tool coatings, and other usesfar too numerous to enumerate.

[0012] Prior utilization of this thin film technology has yielded eithermulti-layered, non-structured, or quantum dot depositions which will bemore fully explained. In each case, these non-structured films at bestprovide some degradation of desirable original qualities for a two ormore component film. Very thin films buckle due to the stress of havinglattice structures slightly different in size from those of thematerials upon which the films are grown. Just a few percent differencein lattice size creates stresses or pressures in a film that can reachup to 10⁵ torr. These huge pressures, when a new layer is deposited onthe top of the first one, force the initially flat film to separate intodots and then top up into the third dimension to relieve stress. Itoccurred that rather than designing around this problem as was the casein the past, it might be possible to control this phenomenon, and haveconsecutive depositions yield three dimensional, anisotropic thin filmswhich maintain the original desired properties of each of the depositedmaterials.

[0013] In the present invention the above described depositiontechniques are employed to fabricate a three dimensional, anisotropicthin film. What is meant by this is that a substrate, which can beviewed for the sake of simplicity as a planar substrate in a horizontalposition, has two or more different materials deposited on its surface.Alternate sequential depositions of the target materials cause each oneto be deposited initially as discrete, separate, individual dots. Eachadditional sequential deposition of the same material then builds up ontop of each initial dot of the material, so that the resultant film iscomposed of two or more multi-columns of each material, the columnsbeing substantially vertical and normal to the planar substrate. Thesecolumns may even be tapered (outwardly or inwardly) as they extend awayfrom the substrate, such as pyramidal in shape.

[0014] To this end a standard physical vapor deposition apparatus wasmodified so as to have precise control over the parameters of PVDdeposition by providing accurate control of the partial pressure ofplasma forming and reactive gases; spectral control of the plasma, inparticular gas characteristics and wave length; accurate control ofinput gas flows, including real time feed-back between the controlsystem and feed gages; real time feed back on deposition parameters;accurate control of gun energy and time; and accurate control ofsubstrate temperature.

[0015] A method has been devised making use of the above controlparameters that, when combined with the tendency of sputtered materialto initially nucleate in small dots forming discontinuous islands with aspecific area coverage ratio, which in turn creates a controllable threedimensional structure. At least two targets (e.g. gold and titanium),whose vacuum sputtering forms a characteristic nano-scale dot formationare used to form a discontinuous island film formation. This island filmformation represents a certain ratio of area coverage versus open andless-conductive spaces between those islands. It is the control of thisnormal tendency of island formation (nucleation), based on specific andwell known material characteristics, that this process is based. Thisnatural structure characteristic is inherent in all sputtered material,which represents, in general, their lowest energy level and theirnegative affinity to each other. A plasma forming gas (e.g. argon) isintroduced into the vacuum chamber, and a reactive gas (e.g nitrogen)may also be introduced into the vacuum chamber to react with at leastone of the target materials. Gas metering is accurately controlled witha gas flow control system (e.g. spectrophotometer, mass flow meter,optical flow control, and other suitable gas flow control systems). Inaddition, gas flow and gas composition within the chamber is furtherrefined with a real-time feed-back system so as to have accurate controlover the partial pressure of the plasma forming and reactive gases.Accurately controlled and timed gun voltage (the power supply to thetargets), together with substrate temperature control, with real- timefeed- back on deposition parameters, and with the two or more targetmaterials being sputter deposited in consecutive order, permits theformation of a three dimensional anisotropic structure. This unique, newstructure preserves the original qualities of each one of the targetmaterials. This structure is in a basic relevant contrast with theclassical multi-layered deposition systems that only display thedominant material characteristics.

[0016] In general the success (S) of the deposition of the structuredfilm can be expressed by the following empirical equation:

S=F(N, V _(1dep) , V _(2dep) , t _(dep) , A)

[0017] Where N is the concentration of forming nuclei, V_(1dep) is therate of deposition of the fist material, V_(2dep) is the rate ofdeposition of the second material, t_(dep) is the time of deposition,and A is the affinity of these materials to each other. Optimalconditions for the deposition of the structured films are in the range:

X₁<S<X₂

[0018] In the case of X₁ we will have a chaotic mixture (or alloy)non-structured film. In the case of X₂ we will obtain a multi-layerdeposition. With the controlled conditions of deposition describedherein, which includes the probability of nucleation, rates ofdeposition, time of deposition and affinity of the two major components,a three dimensional anisotropic structure is obtained. While examplesincluding gold, and titanium are given, it is to be understood that themethod is applicable to any material capable of being sputtereddeposited within the parameters of the method of the present invention.Other materials include, but are not limited to Pd, Al, Cu, C (diamond),or other suitable elements. The “matrix” of the invention can becreated, as one available approach, by reactive deposition of metals(including alloys), which can be a variety of compounds, such as but notlimited to: nitrides (ZrN, CrN, TiAlN); carbo-nitrides (TiCN); carbides(BC, SiC, WC); borides; and oxides (Al₂O₃, Zr O₂) as well as bynon-reactive deposition of other hard metals such as NiCr. Intermetalliccompounds may also be used.

[0019] One embodiment of the present invention provides a threedimensional structure comprising at least two materials capable of beingdeposited by vapor deposition. The structure is fabricated by vapordepositing the at least two materials onto a substrate by controlling afirst deposition of a quantity of one of the at least two materials ontothe surface of the substrate, then controlling a second deposition of asecond one of the at least two materials onto the surface of thesubstrate, and so on, and sequentially repeating these vapor depositionsof a quantity of each one of the at least two materials onto the surfaceof the substrate until an operator determined amount of each one of theat least two materials has been deposited.

[0020] The present invention also provides a three dimensionalanisotropic nanostructure comprising at least two different materials,wherein the nanostructure is user-defined in terms of both geometry andchemical composition in all three dimensions. The nanostructure willretain the exemplary properties of each individual component, and thegeometry and chemical composition can be defined by the user in allthree dimensions. This may be accomplished using vapor deposition of thematerials, such as CVD or PVD.

[0021] The present invention further provides a substrate having acoating thereon, wherein the coating comprises at least two materialscapable of being deposited by vapor deposition. The coating isfabricated by vapor depositing the at least two materials onto thesubstrate by controlling a first deposition of a quantity of a first oneof the at least two materials onto the surface of the substrate, thencontrolling a second deposition of a second one of the at least twomaterials onto the surface of the substrate, and so on, and sequentiallyrepeating the vapor depositions of a quantity of each one of the atleast two materials onto the surface of the substrate until an operatordetermined amount of each one of the at least two materials has beendeposited onto the substrate. The substrate can comprise the surface ofany of a variety of articles on which a coating is desired.

[0022] Another embodiment of the present invention provides a threedimensional structure comprising at least one material capable of beingdeposited by vapor deposition. This structure is fabricated by vapordepositing the at least one material and a second material onto asubstrate by controlling a first deposition of a quantity of a the atleast one material onto the surface of the substrate, then controlling asecond deposition of the second material onto the surface of thesubstrate, and so on, and sequentially repeating the vapor depositionsof a quantity of each one of the materials onto the surface of thesubstrate until an operator determined amount of each one of thematerials has been deposited. Thereafter, the second material isremoved, such as by etching. If desired, an additional material (such asa material which cannot be readily applied by vapor deposition) may beadded to the voids remaining after the second material is removed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a schematic view of a physical vapor depositionapparatus.

[0024]FIG. 2 is a schematic representation of prior art film depositionsas compared with the depositions of the present invention.

[0025]FIG. 3 is a schematic representation of the stresses of prior artdifferential lattice parameters as compared with the stress reliefmethod of expanding into the third dimension of the present invention.

[0026]FIG. 4 is a schematic representation of types of three dimensionalanisotropic structures created by the method of the present invention.

[0027]FIG. 5 is an illustration of a three dimensional anisotropic“carrot” like structure created by the method of the present invention,showing one component as having been etched out of the film.

[0028]FIG. 6 is a chart illustrating the sequential deposition of goldand titanium nitride onto a substrate in accordance with the method ofthe invention.

[0029]FIG. 7A is a schematic, cross sectional representation of a twocomponent film created by the method of the present invention.

[0030]FIG. 7B is a view similar to FIG. 7A showing one of the componentsas having been removed by etching.

[0031]FIG. 7C is a view similar to FIG. 7B showing the empty columnsremoved by etching in FIG. 7B as now being filled with a new, thirdcomponent.

[0032]FIG. 8A is a schematic, cross sectional representation of anothertwo component film created by the method of the present invention.

[0033]FIG. 8B is a view similar to FIG. 8A showing one of the componentsas having been removed by etching.

[0034]FIG. 8C is a top view of the structure depicted in FIG. 8B.

DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention enables the engineered deposition ofvarious films comprising a wide variety of materials, and can produce avariety of engineered structures or coatings. The films may bestructured and user-defined in terms of geometry and chemicalcomposition in all three dimensions. The present invention enablesminiaturization, enhancement of optical, electromagnetic and mechanicalproperties, user-defined geometries and a profusion of surface-specificphenomenon. The invention is capable of producing ultra-thin productswith superior performance in a wide variety of engineered geometrieswhich would otherwise not be possible. The films of the presentinvention also provide cost savings as they require reduced amounts ofdeposited materials in order to achieve the desired performancespecifications.

[0036] We refer now to the drawings wherein similar structures havingthe same function are denoted with the same numerals. In FIG. 2 aschematic representation of a comparison between the vacuum sputterdepositions of the prior art and the present invention is shown. Typicalprior art depositions result in either a multilayer formation (60), anon-structured chaotic layer (62), or a quantum dot formation (64). Inthe present invention a structured alignment (68) of the individualtarget components (12, 14) is obtained as will be more fully explained

[0037] As noted above, very thin films, like those found in conventionaldeposition technologies, are prone to deformation and reducedperformance due to the stresses of differential lattice parametersbetween the substrate and the deposition. These lattice differentialsare also present between multiple systems when deposited on a substrate.These huge stresses are a function of the mobility of adatoms within thedeposition matrix. It occurred that these huge pressures can becontrolled and used advantageously to build preferentially orienteddepositions on a nanometer scale. When new layers are deposited on thetop of the deposition, the initially flat film can be separated intoisolated dots which relieve stress by expanding into the third (Z-axis)dimension as schematically shown in FIG. 3.

[0038] The method of the present invention details the accurate controlof the deposition parameters enabling and defining this stressexpulsion. Under proper conditions consecutive depositions of two ormore materials (12, 14-FIG. 2) can produce three dimensional structuresdefined by the user on a nano to micro scale. The structure formed is afunction of the conditions of the deposition parameters of eachindividual component. The deposition is a function of the followingparameters, which are controlled in order to build the correctlyoriented deposition:

[0039] Accurate control of the partial pressure of plasma forming andreactive gases.

[0040] Spectral control of the plasma, in particular gas characteristicsand wave length.

[0041] Accurate control of input gas flows, including real-timefeed-back between the control system and feed gages.

[0042] Real-time feed-back on deposition parameters.

[0043] Accurate control over gun energy and time.

[0044] Accurate control of substrate temperature.

[0045] As noted above present prior art deposition methodology generateseither multilayer structures (60-FIG. 2), or non-structured composites(62-FIG. 2). A rate of deposition higher than the rate of ordering ofthe deposited layer will produce too thin a layer similar to example 62(FIG. 2). Again, if the deposition results in a too thick layer astructure similar to example 64 (FIG. 2) will result. A “burgeoning”application is one whereby quantum dots (64-FIG. 2) is produced. Quantumdots are in the nanometer size range and are not capable of growingextensively into the Z-direction shown in FIG. 3. The present inventionprovides a method whereby a user can deposit highly structureddepositions that are not restricted along either the X, Y, or Z-axisdepicted in FIG. 3.

[0046] Turning now to FIG. 1 a physical vapor deposition apparatus 10capable of performing the method of the invention is shown. It should benoted that the present invention is not limited to PVD, as CVD may alsobe employed and PVD and CVD may even be employed together in producingfilms according to the present invention. The PVD apparatus 10 in FIG. 1is similar to standard, commercially available equipment as, forexample, Planar Magnetron Balzers Model Bas Pm DC/RF Sputtering System(Balzers Alktiemgessellschaft, Liechtenstein). The vacuum chamber 24 hastwo oppositely positioned gas inlets, a reactive gas inlet 18, and aplasma 28 forming gas inlet 20. Two oppositely positioned entry ports48A provide access for a partial pressure controller orspectrophotometer 48. Two cathodes 16 (or potentially more) areconnected to the lid of the vacuum chamber 24 with different targetmaterials (11, 14) being affixed to the outer surface of each one of thecathodes. Titanium 11 can be the target material on a first one of thecathodes, and pure gold 14 can be the target material on the second oneof the two cathodes. The gold targeted 14 cathode 16 is electricallyconnected to a first power supply 34, and the titanium targeted 11cathode 16 is electrically connected to a second power supply 36. Bothpower supplies are also electrically connected (35, 37) to processor 50.At least one substrate 22 to be coated by the target material ispositioned beneath the cathodes 16, being held in place in this case bya planitaric substrate holder 30. The substrate holder 30 in the examplehas its own power supply 38 electrically connected via insulator 32 atthe base of the vacuum chamber to the substrate holder which can serveas the means for monitoring and temperature controlling the substrate22. The substrate holder 30 has a built-in temperature sensor (notshown) and a heater (not shown) for the purpose of temperaturemonitoring and control. The substrate holder power supply is alsoelectrically connected 39 to a processor 50. On the left side of FIG. 1a source of plasma forming gas 40 is shown connected to a flowcontroller 44 (preferably a mass flow controller), which in turn isconnected to metering valve 46 which then connects to the plasma forminggas inlet 20. Again, at the left of FIG. 1 a spectrophotometer 48 isshown connected to spectrometer entry port 48A, the spectrophotometeralso being connected 56 to a processor (e.g. a personal computer) 50which in turn is connected 58 to the metering valve 46. On the rightside of FIG. 1 a similar gas inlet and control system is shown, with asource of a reactive gas 42 being connected to a flow controller 44(preferably a mass flow controller), which in turn is connected to ametering valve 46, which then connects with the reactive gas inlet 18 atthe opposite side of the vacuum chamber 24. Again, a spectrophotometer48 is shown connected to the vacuum chamber 24 via a spectrometer entryport 48A, the spectrophotometer further being connected 52 to aprocessor 50, which is then connected 54 to the right side meteringvalve 46.

[0047] To use the method of the invention it is first necessary todevelop empirically for given target materials and reactive gases theexact conditions for structured film growth. For example, a test run candetermine the parameters for discontinuous island dot formations for onetarget material, as, for example, determining the porosity of aresultant film. Or direct observation of discontinuous island dotformation can be ascertained with transmission or scanning electronmicrographs. Similarly the parameters for discontinuous island formationis determined for a second target material, and so on. Detailed readilyavailable information on the physical characteristics of each targetmaterial provide data points, which, taken together with test runinformation, will enable the user to custom fabricate structured, threedimensional anisotropic thin films. While the method of the inventioncan be utilized under direct operator control, greater convenience andaccuracy is obtained utilizing an operator programmed processor.

[0048] The method of the deposition of the invention is similar tostandard techniques with additional deposition parameter controls asfollows:

[0049] (1) Prepare the substrate 22. Activate the power supply 38 so asto accurately control the substrate temperature. This is to insure thedesired mobility of the sputtered particles adhering to the substrate.

[0050] (2) Affix at least two target materials (e.g. 11,14) to thecathodes 16.

[0051] (3) Turn on the vacuum pump (not shown) and evacuate the vacuumchamber 24 via the vacuum port 26.

[0052] (4) Introduce a quantity of a plasma forming gas 40 (e.g. argon)into the vacuum chamber via inlet 20, making use of the flow controller44 and metering valve 46.

[0053] (5) Turn on the first gun (power supply #1, 34-FIG. 1). At thesame time as the power supply 34 is turned on the spectrophotometer 48is turned on. It is important to note that simple controlled metering ofgases into the vacuum chamber is inadequate. The partial pressure of anygases used must be known and this information processed by a means forcontrolling the process (e.g. processor 50) so as to further regulatethe admitted quantity of gas via the metering valve 46. This isessential so that the precise quantity and particle size of thesputtered target material (11, 14) is created and maintained. Theempirical power voltage/partial pressure relationship for each targetmaterial as ascertained in trial runs is made a part of the controlprogram within the processor 50.

[0054] (7) Accurately control power supply 34, 36 voltage and the timeof activation.

[0055] (8) Accurate control the temperature of the substrate 22.

[0056] (9) Permit a deposition of the first target material 14 for aspecific period of time.

[0057] (10) If the second target material 11 is to be reacted with a gasthe first power supply 34 is turned off and a quantity of a reactive gas42 is metered into the vacuum chamber 24 using the flow controller 44,metering valve 46, and the inlet 18.

[0058] (11). Turn on the second gun (power supply #2, 36-FIG. 1). At thesame time turn on the spectrophotometer so that the empirical powervoltage/partial pressure relationship of the second target material asprogrammed into the processor 50 enables the production of an accuratequantity and particle size of this second sputtered target material. Inregards to this second target material, the sputtered target materialwill be deposited on the substrate as a compound of the original targetmaterial and reactive gas (e.g. titanium nitride 12).

[0059] (12) Permit a deposition of the second reactive target materialfor a period of time.

[0060] (14) Sequentially repeat the precisely timed depositions for eachtarget material until a suitable layer of film (as previously operatordetermined and incorporated into the program of the processor) has beendeposited. The above method can be manually monitored and controlled byan operator. Obviously a control system, such as a processor 50programmed to perform some or all of the steps of the method willincrease accuracy and convenience.

[0061] The differences of the results of this process to standardtechniques are best seen in FIGS. 2-4. Standard method parametersinevitably lead to the formation of intermediate layers of materialalong the X and Y axes, down playing the tendencies of these films towant to expand into the Z axis. As shown in FIG. 2 this results inmulti-layered, non-structured, or quantum dot formation. In the methodof the invention, shown at the far right in FIG. 2, depositions arecontrolled into non-continuous individual films. FIG. 4 is a schematic,sectional view of the typical three dimensional anisotropic structuresproduced. A, B and C depositions represent different “carrot” typeshapes produced. Examples D and E demonstrate that semi-encapsulated andencapsulated structures may be produced. Example F is a top plan view ofthe structures of A, B, C, and D.

[0062] As note above, the method of the invention defines the systeminto a controllable environment whereby depositions are controlled so asto form non-continuous, individual films. Intermediate layers are notformed.

SPECIFIC EXAMPLE

[0063] The following is an example of the method of the invention inwhich an anisotropic three dimensional film of gold and titanium nitrideis produced.

[0064] Wearer-Resistant Gold-Like Coating Deposition Particulars:

[0065] Substrates were cleaned and prepared per standard deposition

[0066] Substrates were loaded into the vacuum chamber, vacuumestablished and heated with rotation to the deposition temperature (200°C.) and allowed to stabilize for 10 min.

[0067] Ar was bleed into the system to the operating pressure (3 mtorr)for Ti magnetron ignition (arcing)

[0068] A 40 nm thick Ti deposition was deposited as the adhesion layer,deposition rate=0.2 nm/s.

[0069] Nitrogen (5 mtorr) was introduced and deposition of the initialTiN layer was effected: 17 min at a rate of 0.26 nm/s, final thicknessequaled 270 nm.

[0070] 1. Nitrogen was switched off, Au target was switched on and adeposition of 0.6 nm of Au at a rate of 0.03 nm/s (gold “carrots”nucleation stage) was effected;

[0071] 2. Nitrogen switched on (5 mtorr) and deposition of 11 nm of TiNat a rate of 0.3 nm/s;

[0072] 3. Nitrogen was switched off, Au target was switched on and adeposition of 1.1 nm of Au at a rate of 0.03 nm/s was effected.

[0073] 4. Nitrogen switched on (5 mtorr) and deposition of 11 nm of TiNat a rate of 0.3 nm/s;

[0074] 5. Nitrogen was switched off, Au target was switched on and adeposition of 2.2 nm of Au at a rate of 0.05 nm/s was effected.

[0075] 6. Nitrogen switched on (5 mtorr) and deposition of 11 nm of TiNat a rate of 0.3 nm/s;

[0076] 7. Nitrogen was switched off, Au target was switched on and adeposition of 3.4 nm of Au at a rate of 0.08 nm/s was effected

[0077] 8. Nitrogen switched on (5 mtorr) and deposition of 12 nm of TiNat a rate of 0.23 nm/s;

[0078] 9. Nitrogen was switched off, Au target was switched on and adeposition of 4.5 nm of Au at a rate of 0.1 nm/s was effected

[0079] 10. Nitrogen switched on (5 mtorr) and deposition of 13 nm of TiNat a rate of 0.2 nm/s;

[0080] 11. Nitrogen was switched off, Au target was switched on and adeposition of 5.6 nm of Au at a rate of 0.13 nm/s was effected;

[0081] 12. Nitrogen switched on (5 mtorr) and deposition of 10 nm of TiNat a rate of 0.2 nm/s;

[0082] 13. Nitrogen was switched off, Au target was switched on and adeposition of 6.7 nm of Au at a rate of 0.16 nm/s was effected;

[0083] 14. Nitrogen switched on (5 mtorr) and deposition of 10 nm of TiNat a rate of 0.16 nm/s;

[0084] 15. Nitrogen was switched off, Au target was switched on and adeposition of 7.9 nm of Au at a rate of 0.19 nm/s was effected;

[0085] 16. Nitrogen switched on (5 mtorr) and deposition of 7.2 nm ofTiN at a rate of 0.16 nm/s;

[0086] 17. Nitrogen was switched off, Au target was switched on and adeposition of 9.0 nm of Au at a rate of 0.22 nm/s was effected;

[0087] 18. Nitrogen switched on (5 mtorr) and deposition of 7.0 nm ofTiN at a rate of 0.12 nm/s;

[0088] 19. Nitrogen was switched off, Au target was switched on and adeposition of 9.0 nm of Au at a rate of 0.22 nm/s was effected

[0089] 20. Nitrogen switched on (5 mtorr) and deposition of 3.0 nm ofTiN at a rate of 0.1.

[0090] All gases were switched off, the sample was cooled to 120° C. andthe samples were removed from the vacuum chamber.

[0091]FIG. 6 shows a schematic representation of the steps involved inthe formation of a gold-titanium nitride film, such as a structuresimilar to that depicted in FIG. 8A.

[0092] One method employed to demonstrate the actual “carrot-like”anisotropic three dimensional structure achieved was to etch theresultant film in a mixture of hydrochloric acid and nitric acid (aquaregia) which is known to dissolve gold. A schematic representation ofthe result of etching structure 68 in FIG. 2 is shown in FIG. 5.

[0093] As shown in FIGS. 7A, 7B, and 7C the above described etchingprocess provides additional novel applications for these threedimensional anisotropic thin films. FIG. 7A illustrates a possiblestructure for a two component film of titanium nitride 12 and gold 14.In FIG. 7B the gold component of this film has been completely removedby etching, as, for example, utilizing a mixture of hydrochloric acidand nitric acid. This unique structure now permits a number ofinteresting applications such as miniature molecular sieves, filters, ortemplates for nanowires. In FIG. 7C the empty columns 70 shown in FIG.7B are now shown filled with a material different from the originalmaterial of deposition, as, for example, graphite 72. This example oftitanium nitride and graphite could be used to facilitate lubricationfor a nano-dimensional polishing disc. This introduction of a newcomponent into etched films produced by the method of the invention canbe effected in a number of ways, as, for example, field assistedadsorption, capillary action, electrochemical reaction, and mechanicalmeans.

[0094]FIG. 8A depicts another exemplary structure for a two componentfilm of titanium nitride 12 and gold 14. In the film of FIG. 8A, the“columns” or carrot-like structure essentially comprise pyramides,wherein the base of the TiN “pyramids” are positioned directly on top ofthe substrate while the Au “pyramids” are inverted. Depending upon thedesired properties of the structure depicted in FIG. 8A, the peaks ortips of the inverted Au “pyramids” may or may not extend all the way tothe surface of the substrate. Likewise, once again depending on thedesired properties of the structure, the peaks or tips of the TiN“pyramids” may or may not extend the same distance away from the surfaceof the substrate as the base of the Au “pyramids.” In other words, thetip or peak of the TiN “pyramids” may or may not be visible in a topplan view of the film shown in FIG. 8A.

[0095] In the same manner as described previously, the gold component ofthe structure depicted in FIG. 8A may be removed by etching, as, forexample, utilizing a mixture of hydrochloric acid and nitric acid. Theresulting structure is depicted in FIG. 8B, and a top plan view of aportion of this structure is depicted in FIG. 8C. As before, the emptyinverted “pyramid” regions in FIG. 7B may even be filled with a materialdifferent from the original material of deposition, as, for example,graphite.

[0096] The film depicted in FIG. 8A may be used, for example, as a wearresistant coating on the surface of an article (i.e., the substrate),particularly articles used in the electronics industry. The coating willretain the electrical and optical performance of gold, coupled with thestrength and toughness of TiN. The film depicted in FIG. 8B provides anearly perfect TiN polishing surface. If a carbide polishing surface isdesired, a suitable carbide may be used in place of TiN.

[0097] Thus a unique new method for depositing single or multi-componentcomposite systems via vacuum deposition is disclosed. The method allowsthe formation of preferential growth of discreet formulae within thecomposite matrix. Results include increased performance and novelapplications of the depositions. The method allows for enhanced optical,mechanical, adhesive, compositional, hardness, toughness, wearresistance, reflectance and electrical control and performance. Further,novel structures not heretofore possible can be fabricated.

[0098] By way of further examples, if a nano-dimensional template or anano-dimensional filter is required, the materials (e.g., TiN and Au)can be deposited in a cylindrical form (e.g., structure D in FIG. 4).Upon etching of one of the materials (e.g., Au), the resulting structure(e.g., TiN) will have cylindrical pores extending along one axis. Thesepores can be used, for example, as a template for the production ofnano-dimensional wires by, for example, capillary action.

[0099] This present invention is applicable over a very wide range ofnovel applications as well as an enhancement and replacement of existingtechnologies. The ability to utilize this technology on existingequipment, with small modifications, enables its wide range applicationin a cost-effective manner. A short list of potential applicationsincludes:

[0100] Wear Resistant Conductive Thin Films

[0101] Applications abound in the electronics industry,telecommunications and systems utilizing electrical and mechanicalcontacts.

[0102] Wear Resistant Decorative Plating

[0103] Coatings for jewelry, silverware and decorative fixtures. Thepresent invention can be employed to produce coatings which have highwear resistance, and even coatings which comprise high levels of costeffective materials and low levels of expensive materials with increasedperformance while maintaining the appearance of precious metals.

[0104] Strength Enhanced Coatings

[0105] The present invention can be applied to stamping and cuttingapplications, as well as automotive, aerospace, medical and structuralcomponents. For example, cutting tools can be produced using costeffective materials and subsequently coated with a structured materialto increase strength and toughness. Used tools can also be re-coated tooriginal dimensions. Structured depositions will greatly prolong toollife. Coatings may prolong and protect CD's, by itself a multi-billiondollar industry. Other applications include medical tools, precisionmechanical tools, drill bits, coatings for machined parts used inabrasive environments, bearings, and optical coatings.

[0106] Abrasive Thin Film Media

[0107] With the development of miniaturized technology, finelycontrolled abrasive thin films will enable extremely fine control overpolishing depths and defect sizes. Abrasive thin films of this type mayfind many new applications.

[0108] Wear Resistant Optical

[0109] The introduction of fiber optics to replace conventionalconnection and transmission lines may require novel structures to enablecontacts, switches and protective coatings. Ultra thin coatings may alsoenable user-defined applications such as corrosion resistance usingsilver nitride and integration possibilities. User defined coatings mayalso enable the coating of engineered systems to replace breakable glassand to facilitate optical to electrical junctions.

[0110] Quantum Dot Arrays

[0111] This is a relative new field with applications in R & D,medicine, drug delivery and novel optical applications. Some examplesinclude nano-dimensional reversible media, field emission nano-tiparrays based on metal dots, diamond like materials and thermo-stablequantum dot arrays.

[0112] Optical Coating with 3D Anisotropy

[0113] With the expansion of the space program and ballistic missiletechnologies, reflective coatings for harsh environments have become aconcern. Optical reversible media for harsh environments, polarizedreflective films, interference filters, and cylindrical magnetic opticaldomains are possible with the deposition technology of the presentinvention.

[0114] Nanodimensional Templates

[0115] Nanodimensional-template structures or filters produced fromnitrides, oxides, carbides, silicides or other materials are directapplications of the present invention. Applications such asnano-dimensional sieves for genetic materials, user defined porousstructures for refining, catalytic and fuel cell membranes are a smallsample of potential applications.

[0116] Precision Mechanical Devices and MEMS/NEMS

[0117] Immediate applications include precision coatings with exactdimensions for MEMS, NEMS, IR and UV-VIS mirrors, and engineeredcoatings designed for multitasking applications.

[0118] While the present invention has been disclosed in connection withversions shown and described in detail, various modifications andimprovements will become readily apparent to those skilled in the art.Accordingly, the spirit and scope of the present invention is to belimited only by the following claims.

What we claim is:
 1. A three dimensional structure comprising at leasttwo materials capable of being deposited by vapor deposition, saidstructure fabricated by vapor depositing said at least two materialsonto a substrate by controlling a first deposition of a quantity of afirst one of said at least two materials onto the surface of thesubstrate, then controlling a second deposition of a second one of saidat least two materials onto the surface of the substrate, and so on, andsequentially repeating said vapor depositions of a quantity of each oneof said at least two materials onto the surface of the substrate untilan operator determined amount of each one of said at least two materialshas been deposited.
 2. A three dimensional anisotropic nanostructurecomprising at least two different materials, wherein said nanostructureis user-defined in terms of both geometry and chemical composition inall three dimensions.
 3. A substrate having a coating thereon, saidcoating comprising at least two materials capable of being deposited byvapor deposition, said coating fabricated by vapor depositing said atleast two materials onto said substrate by controlling a firstdeposition of a quantity of a first one of said at least two materialsonto the surface of said substrate, then controlling a second depositionof a second one of said at least two materials onto the surface of saidsubstrate, and so on, and sequentially repeating said vapor depositionsof a quantity of each one of said at least two materials onto thesurface of said substrate until an operator determined amount of eachone of said at least two materials has been deposited onto saidsubstrate.
 4. A three dimensional structure comprising at least onematerial capable of being deposited by vapor deposition, said structurefabricated by vapor depositing said at least one material and a secondmaterial onto a substrate by controlling a first deposition of aquantity of said at least one material onto the surface of thesubstrate, then controlling a second deposition of said second materialonto the surface of the substrate, and so on, and sequentially repeatingsaid vapor depositions of a quantity of each one of said materials ontothe surface of the substrate until an operator determined amount of eachone of said materials has been deposited, and thereafter removing saidsecond material.
 5. The three dimensional structure of claim 4, whereinsaid structure further comprises an additional material, and furtherwherein said additional material is added to voids remaining after saidsecond material is removed.
 6. The three dimensional structure of claim5, wherein said second material is removed by etching.
 7. The threedimensional structure of claim 5, wherein said additional materialcomprises a material which cannot be applied by vapor deposition.